I have this thought experiment for designers that's inspired by the term "retronym". A retronym is a new name given to something old because something newer comes along. If that's confusing, here are some examples:

live music used to just be called music until recorded music came along.

acoustic guitars used to just be called guitars until electric guitars became popular. Now they're sometimes just called acoustics as in, "I just bought an acoustic."

horsecars used to just be called cars.

When a new technology comes along, you actually gain a newfound appreciation for the old one. Maybe this is borne out of nostalgia, or maybe it's because the stalwarts become vocal defenders of the dying medium (oftentimes because their business model depends on it). Sometimes, this leads to a retrofitted innovation wherein aspects of the new medium cross-pollinate the old one (similar to how touch interfaces like the iPhone are influencing Mac OS and Windows).

This thought process helps me come up with ideas for new apps. Imagine that everything you own today will be some future generation's nostalgia. How does that change the way you think? Here are a few that came to me while daydreaming:

Televisions are large iPads

Television is a larger iPad that you place fifteen feet in front of you, not fifteen inches. Because it's further away, there's less eye strain and therefore it's more relaxing. It's hands-free. Once you load your favorite show, you can put the UI away and lay out on the couch. If you want to stretch or readjust, you don't have to move the screen. There's actually less UI to fuss with on a TV than an iPad. On the iPad, you're just two-taps away from the complicated GUIs for Mail and Safari. TV is distraction-free and immersive. It's not the place where you conduct your work; it's exclusively for entertainment. And it's more social, allowing for amphitheater-style viewing without any complicated set-up: all someone has to do to join your social network is enter the room.

Live music is an album-listening party with a 3D-audiovisual accompaniment

What is live music? At one point, all music was live and it was just called "music," but now I think live music is getting a newfound appreciation, as well as higher price point to distinguish itself from the myriad alternatives, the simplest of which is putting on headphones, lying down, and listening to your favorite band's latest album, front-to-back. Live music, on the other hand, provides a 3D visual accompaniment to an album. The accompaniment is improvised, so there's anticipation, mystery, and the potential for danger. There's an interactive component as well, where the players and the audience members participate in a feedback loop. Plus the listening party is outdoors, there's a better sound system, and there's a sense of shared camaraderie. Whereas when you listen to an album at home, you don't really know whether you're the only person who likes this.

Books are self-contained content dumps

What is a book? A book is one of those awesome websites or PDFs where you have 50,000+ words on a single topic, and it's all organized in a linear browsing fashion. The pages are long and continuous, with no breaks or jumps designed to maximize page views. It's free from ads and clutter and it has minimal spelling errors. The content is usually from an expert on the topic, and the expert is vetted by pros (editors). This gives you confidence that you're not just reading a loquacious screed posted from some lunatic on their free hosting site. I love bumping into these kind of "books", which usually happens once every two months. Fortunately there are actual books which are pretty much the same thing, and all you have to do is go to amazon, where millions of these these content treasure troves are a few clicks and a credit card away.